U.S. patent number 5,495,709 [Application Number 08/286,211] was granted by the patent office on 1996-03-05 for air reservoir turbine.
This patent grant is currently assigned to ABB Management AG. Invention is credited to Hans U. Frutschi.
United States Patent |
5,495,709 |
Frutschi |
March 5, 1996 |
Air reservoir turbine
Abstract
In an air reservoir turbine, comprising a gas turbine group
connected for selectable delivery of compressed air from a
compressor unit and a compressed air reservoir, and including a hot
water reservoir and a waste heat steam generator downstream of the
gas turbine group, an amount of steam from the waste heat steam
generator is introduced into the gas turbine group and is used for
increasing its output. Additionally, hot water from various
intercoolers and a heat exchanger is generated in connection with
the compressor unit of the gas turbine group. The amount of steam
obtained therefrom is admixed to the compressed working air and is
used as combustion air for operating the gas turbine group.
Inventors: |
Frutschi; Hans U. (Riniken,
CH) |
Assignee: |
ABB Management AG (Baden,
CH)
|
Family
ID: |
4234175 |
Appl.
No.: |
08/286,211 |
Filed: |
August 5, 1994 |
Foreign Application Priority Data
|
|
|
|
|
Aug 5, 1994 [CH] |
|
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02 453/94 |
|
Current U.S.
Class: |
60/39.55;
60/727 |
Current CPC
Class: |
F02C
6/16 (20130101); F01K 21/047 (20130101); F05D
2260/211 (20130101); Y02E 60/15 (20130101); Y02E
60/16 (20130101) |
Current International
Class: |
F02C
6/00 (20060101); F02C 6/16 (20060101); F01K
21/04 (20060101); F01K 21/00 (20060101); F02C
007/00 () |
Field of
Search: |
;60/727,39.02,39.05,39.53,39.55,39.59 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Thorpe; Timothy S.
Attorney, Agent or Firm: Burns, Doane, Swecker &
Mathis
Claims
I claim:
1. An air reservoir turbine installation having a gas turbine group
connected to a compressed air reservoir, and comprising a hot water
reservoir, a waste heat steam generator connected to receive an
exhaust gas flow downstream of the gas turbine, the gas turbine
group comprising a compressor unit, at least one combustion chamber
and at least one turbine, wherein the waste heat steam generator is
connected to introduce steam into the gas turbine group for
increasing an output of the at least one turbine, and further
comprising at least one heat exchanger to cool working air
compressed by the compressor unit and a partial pressure evaporator
to introduce water vapor into the working air, the at least one
heat exchanger being connected to deliver heated water to the
partial pressure evaporator.
2. An air reservoir turbine in accordance with claim 1, the hot
water reservoir is connected to deliver hot water to the partial
pressure evaporator the at least one heat exchanger being connected
to deliver heated water to the hot water reservoir.
3. An air reservoir turbine in accordance with claim 1, the
compressor unit comprising three compressors and an intercooler
interposed between a first and a second compressor and between the
second compressor and a third compressor.
4. An air reservoir turbine in accordance with claim 3, wherein the
intercoolers are connected to deliver heated water to the hot water
reservoir for selectable introduction into the working air via the
partial pressure evaporator.
5. An air reservoir turbine in accordance with claim 1, wherein the
waste heat steam generator is connected to introduce steam into the
working air flow at the at least one combustion chamber of the gas
turbine group.
6. An air reservoir turbine in accordance with claim 1, wherein the
compressor unit and turbine are disposed on separate shafts and
each shaft having an electrical machine.
7. An air reservoir turbine in accordance with claim 1, wherein the
compressor unit and turbine are disposed on a single shaft having
an electrical machine.
8. A method for operating an air reservoir turbine installation
having a gas turbine group connected to a compressed air reservoir
as a selectable source of compressed air, and comprising a hot
water reservoir, a waste heat steam generator connected to receive
an exhaust gas of the gas turbine, the gas turbine group comprising
a compressor unit with heat exchangers to cool compressed air, at
least one combustion chamber and at least one turbine, the method
comprising the steps of:
introducing steam generated in at least one pressure stage in the
waste heat steam generator to working air in the at least one
combustion chamber or immediately downstream of the at least one
combustion chamber;
injecting heated water generated in the heat exchangers into a
partial pressure evaporator to produce vapor under partial
pressure; and
introducing the vapor into the working air upstream of the at least
one combustion chamber.
9. A method in accordance with claim 8, wherein during operation in
which the air reservoir is charged by the compressor unit, the
method comprising the steps of driving the compressor unit with an
electrical machine operating as a motor, directing hot water
generated in the heat exchangers for storage to the hot water
reservoir, and directing compressed air from the compressor for
storage to the compressed air reservoir.
10. A method in accordance with claim 8, wherein during operation
of the at least one turbine with the at least one combustion
chamber an electrical machine mounted on a shaft on which the
turbine is mounted is operated as a generator, the method
comprising the steps of supplying compressed working air from the
compressed air reservoir and at least partially saturating the
compressed working air in the partial pressure evaporator with
evaporated water from the hot water reservoir.
11. A method in accordance with claim 8, during full-load operation
of the gas turbine group wherein the compressor unit is operated to
provide compressed air to the turbine group, the method comprising
the steps of:
directing compressed air in excess of a demand of the turbine group
to the compressed air reservoir for storage;
wherein, when compressed air is directed to the compressed air
reservoir, a net addition of hot water from the heat exchangers is
stored in the hot water reservoir.
12. A method in accordance with claim 8, wherein during periods of
peak demand for electricity from the turbine group wherein the
compressor unit is not operated, the method comprising the steps
of:
directing compressed air from the compressed air reservoir to the
turbine group; and
directing hot water from the hot water reservoir to the partial
pressure evaporator, wherein there is a net subtraction of hot
water from the hot water reservoir.
Description
FIELD OF THE INVENTION
The present invention relates to an air reservoir turbine. The
invention also relates to a method for operating an air reservoir
turbine.
BACKGROUND
So-called air reservoir turbines are known, wherein the compressor,
motor-driven by the generator, fills a compressed air reservoir and
in this way indirectly stores electrical energy during partial load
operations. During high load operations the stored compressed air
is expanded in the turbine in a state where it is heated by fuel,
in the course of which the output obtained in this manner is
completely delivered to the power grid. In the process such air
reservoir turbines can be supplemented by a steam circuit connected
downstream of the turbines.
It has also known that such air reservoir turbines can be operated
as pure gas turbines during the time the compressor and the turbine
are operated for connected simultaneous operation. In this case it
is possible to connect the compressed air reservoir as a
controllable capacity for regulating the output.
In the case where the installation primarily operates in the
reservoir mode for supplementing peak demands, the maximally
possible output potential is not yet achieved, which has a strong
negative influence on the efficiency of the installation.
SUMMARY OF THE INVENTION
The invention is intended to bring relief here. Its object, as
distinguished in the claims, is to maximize the output and
efficiency of an air reservoir turbine and of the method of
operating such an air reservoir turbine of the type mentioned at
the outset.
This object is attained in accordance with the invention in that
the recuperation of the turbine exhaust gases as well as the waste
heat of the intercooler of the compressor unit is initiated.
Steam is generated in at least one pressure stage in a waste heat
generator downstream of the gas turbine group, which is added to
the compressor air, if possible prior to or during the combustion
of the fuel, so that the turbine output is increased by
approximately 30 to 40%.
The energy consumption of the compressor unit is reduced on the
compressor side by at least one intermediate cooling of the
compressed air, and the compressor heat recovered from the
compressed air is used for heating pressurized water. This
pressurized water is then injected in a partial pressure compressor
into the relatively cold steam air, so that partial evaporation
under partial pressure can take place. By means of this 15 to 20%
of water vapor are also admixed to the compressed air, so that the
turbine output is again increased by approximately 30 to 40%.
To maintain this operating principle also during reservoir
operation, a hot water reservoir is also required in addition to
the compressed air reservoir. The water evaporated in the partial
pressure compressor must be continuously replaced by fresh
water.
A replacement of the waste heat steam generator by a recuperator
for pre-heating the compressed air downstream of the partial
pressure compressor is also per se possible. The result of such an
arrangement is that, although the efficiency is increased, the
output of the turbine is weakened because of the lacking steam
portion.
There is, of course, the option of a partial recuperation of the
hot turbine exhaust gases for pre-heating the air, in the course of
which the steam generation in the waste heat steam generator is
correspondingly reduced. This step can be used for optimizing the
air reservoir turbine.
Advantageous and practical further embodiments of the attainment of
the object of the invention are disclosed in the further dependent
claims.
An exemplary embodiment of the invention will be explained in
detail below by means of the drawings. All elements not needed for
directly understanding the invention have been omitted. The flow
direction of the media is identified by arrows.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an air-steam reservoir power plant in accordance with
the invention.
FIG. 2 shows the power plant of FIG. 1 with the compressor unit and
the turbine installed on separate shafts.
DETAILED DESCRIPTION
The drawing figure shows an air-steam reservoir power plant, the
units of which are a gas turbine group, a waste heat steam
generator 25, a compressed air reservoir 5 and various further
reservoir or auxiliary units. The gas turbine group itself
comprises a compressor unit 1 consisting of a plurality of
compressors 1a, 1b, 1c, which operates upstream of a combustion
chamber and turbine system 14, 17; 19, 22. The waste heat steam
generator 25 for providing steam, which is generally returned to
the gas turbine group, is connected downstream of the last turbine
22. The final, compressed air 4 from the last compressor 1c either
flows into a compressed air reservoir 5 or, via a branch line into
a partial pressure evaporator 11 located upstream of a first
combustion chamber 14, the high-pressure combustion chamber, i.e.
the final compressed air 4 flows directly into the compressed air
reservoir 5, or directly into the partial pressure evaporator 11,
or partially into the compressed air reservoir 5 and, as required,
partially into the partial pressure evaporator 11. The following
circuits and operation result in connection with the remaining
auxiliary units: the aspirated air 3 first flows into a first
compressor 1a, in which a first partial compression takes place.
This pre-compressed air 3a subsequently passes through a first
intercooler 2a until it is admitted at reduced temperature into a
second, downstream compressor 1b. This additionally compressed air
3b passes through a further, downstream intercooler 2b before it is
finally directed into a third compressor 1c, in which final
compression takes place. Subsequently this final compressed air 4
flows through a heat exchanger 6, located upstream of the already
mentioned compressed air reservoir 5, in which a third cooling
process takes place. A line 8 branches off upstream of this
compressed air reservoir 5, which provides compressed work air and
is basically used as a take-out line or through which final
compressed cooled air 7 flows. This alternating connecting option
is maintained by a number of control elements 9 which are
appropriately triggered. The following relates to the compressed
air reservoir 5: it receives the compressed cooled air 7 of the
last compressor 1c, and the compressors 1a, 1b, 1c are driven by
means of the electrical device 12, now operated as a motor, and in
this way receive the energy to be stored from the power net. As
shown in FIG. 2, the turbine 17, 22 and the compressor unit 1 may
be installed on separate shafts with a generator 12a on the turbine
shaft. In both cases, namely during the connected gas turbine
operation as well as during the discharge operation of the
compressed air reservoir 5, the relatively cold compressed work air
flows initially into the partial pressure evaporator 11, in which
mixing with a portion of hot water takes place via a line 40 from
an upstream operating hot water reservoir 10, the connective
availability of which will be described in detail further down
below. A partial evaporation under partial pressure of the hot
water 40 takes place by the injection of the portion of hot water
40 upstream of the first combustion chamber in such a way that
basically a first water vapor portion of a magnitude of 15 to 20%
is admixed to the work air flowing through the line 8.
Subsequently, this air/water vapor mixture 13 flows as combustion
air into the high pressure combustion chamber 14 in which hot gases
16 are generated by means of adding a fuel 15, which subsequently
charge a high pressure turbine 17. The exhaust gases 18 from this
high pressure turbine 17 are brought into a low pressure combustion
chamber 19, in which, with the addition of a fuel 20, a further
caloric processing of the heating gases 21 takes place. The latter
then charge a low pressure turbine 22, in which first the final
expansion takes place. The exhaust gases from there are passed
through the waste heat steam generator 25 in which steam is made
available at different pressure levels. A portion of steam 26 of
higher pressure is infused in the high pressure combustion chamber
14, another portion of steam 27 of lower pressure is infused into
the low pressure combustion chamber 19. The water supply of the
waste heat steam generator 25 is symbolized by the schematically
represented line 29 with the associated feed pumps 30. This
addition of steam has a dual purpose: first, the respective turbine
output is increased by 30 to 40% then the NOx emissions are
minimized by the effect of the steam on the flame temperature. The
exhaust gases, which have been fully used calorically by the waste
heat steam generator 25 then flow outside via a chimney in the form
of flue gases 28. The circuits of this air-steam reservoir power
plant have a second water circuit which is in operative connection
with all intercoolers 2a, 2b associated with the compressors 1a,
1b, 1c, with the heat exchanger 6 operating downstream of the last
compressor 1c as well as the hot water reservoir 10 operating
upstream of the partial pressure evaporator 11. A water supply line
31 replaces the water evaporating in the partial pressure
evaporator 11 which, admixed to the final compressed work air 8,
escapes via the combustion chambers 14, 19, turbines 17, 22 and the
waste heat evaporator 25 through the chimney 28. Otherwise a
circulating water flow 33, divided into partial flows 35, 36, 37,
takes over the heat removal in the coolers 2a, 2b and 6. By means
of this the water is brought to a high temperature level and is
supplied via the line 39 and the hot water reservoir 10 to the
partial pressure evaporator 11 via a line 40.
* * * * *